In motor vehicles, controllers with an electronic control unit and with associated components, such as sensors, are used for various tasks. When they are used in a gearbox, for example, rotational speeds of shafts and positions of speed selectors are sensed by means of sensors. On the basis of this information, the electronic control unit controls, among other things, gear shifting in the gearbox. The electronic control unit is usually arranged on a carrier plate and enclosed by a housing body. The sensors are separated from the electronic control unit and positioned in the immediate vicinity of the parts to be sensed and are electrically connected to the electronic control unit via electric conductors, particularly via pressed screens; this arrangement is determined by the application. The pressed screens are usually plastic-coated by injection-moulding around them and form, together with the sensor as an electric component and with a sensor cover, a component carrier (also called sensor dome).
When several component carriers are used, they are particularly coated as a whole by injection-moulding around them in an injection-moulding process to form a single monolith. This monolith is usually a part of the housing body that encloses the electronic control unit, said housing body being connected to the carrier plate preferably by screwing, caulking or riveting. Thus, the sensor can be electrically connected to the electronic control unit on the carrier plate via the pressed screen in the component carrier and particularly via a flexible foil conductor that is laminated onto the carrier plate.
The completed controller may be connected to a system interface, for example to a gearbox or to hydraulic equipment. The tolerance chains in the step of positioning the sensor relative to the part to be sensed, with the connection between the controller and the system interface as a reference point, are on the one hand particularly dependent on the tool parameters during the manufacture of the monolith, and on the shrinkage processes after coating the component carriers as a whole by injection-moulding around them. Connecting the monolith or the housing body to the carrier plate may result in a further tolerance chain. If there are any subsequent furnace processes, they may cause additional inaccuracy with respect to the positioning of the sensor.